RFI: Are these Polish markings, or something else?

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I'm trying to identify the markings on this Gewehr 98-style bolt, which was found in 'duffle cut' Belgian Model 1935 rifle. The bolt obviously doesn't match the rifle, but I can't identify it's origin. It was blued in a manner and tone consistent with the bluing used in WWII German depots, so I think that might be part of it's heritage. Any information would help.

Thank you,
Pat